From an article by Gary Galles on the Foundation for Economic Education website:
February 5 marks the birth of the American who had the greatest hand in what became the 4th Amendment’s prohibition of unreasonable searches and seizures – James Otis. Unfortunately, “one of the most passionate and effective protectors of American rights” is too-little remembered today.
Otis’ efforts applied the celebrated English maxim, “Every man’s house is his castle” – or, as William Pitt said in Parliament in 1763, that “The poorest man may in his cottage bid defiance to all the force of the crown” – to the colonies, in resistance to Crown-created writs of assistance. They were broad search warrants enabling customs officials to enter any business or home without advance notice, probable cause, or reason, which Otis asserted were unconstitutional.
A young John Adams listened to Otis' anti-writs oration, at which "the child's independence was then and there born." Otis was an advocate general in the vice-admiralty court with responsibilities including prosecuting smuggling, to which Britain’s onerous trade restrictions had turned many. But when the Crown imposed writs of assistance to crack down, Otis resigned his post in protest and represented, without charge, Boston merchants’ efforts to stop the writs. For five hours he argued that they violated citizens’ natural rights, putting them beyond Parliament’s powers. A young John Adams listened to Otis’ oration, at which “the child's independence was then and there born.”